JP2004132037A - Circulating flushing toilet and sewage purification method of the circulating flushing toilet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circulating flushing toilet obtaining a stably colored treated water and a sewage purification method of the circulating flushing toilet. <P>SOLUTION: The circulating flushing toilet 1 decomposes an organic matter contained in sanitary sewage from a flushing toilet 5 by a biological treatment tank 6 and, at the same time, it is treated as nitrification and denitrification. Biologically treated water biologically treated by the biological treatment tank 6 is separated into solid-liquid by a filter tank 7, and filtrate is treated as oxidation/decoloration with ozone by a decoloring tank 8. The treated water treated by oxidization (colorization) is temporarily stored in a treated water tank 10, and it is returned to the flushing toilet 5 to reuse it as flushing water. Color of the treated water is continuously/intermittently measured by a color meter 9, and an easy decomposable organic matter stored in an easy decomposable organic matter tank 13 is supplied to the biological treatment tank 6 by controlling a pump 12 with a controller 11 based on the color. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a circulating flush toilet that purifies sewage water and circulates the flush water as flush water, and a method for purifying sewage of a circulating flush toilet.
[0002]
[Prior art]
BACKGROUND ART A circulating flush toilet that purifies sewage water and circulates the flush water as flush water has been developed and put into practical use. As shown in FIG. 5, in the conventional circulating flush toilet 100, sewage from the flush toilet 105 is first subjected to organic matter decomposition, nitrification, and denitrification in a biological treatment tank 110, and then solid-liquid separation in a filtration tank 120. You. The filtered water that has been subjected to solid-liquid separation enters the decolorization tank 140, where ozone is blown into the decolorization tank 140 to be decolorized by oxidation, and is temporarily stored in the treated water tank 150. Then, the stored treated water is returned from the treated water tank 150 to the flush toilet 105 as washing water.
[0003]
[Problems to be solved by the invention]
However, in the circulating flush toilet configured as described above, the organic matter treatment can be sufficiently performed, but the nitrogen removal may be insufficient depending on the properties of the sewage. In particular, when the ratio of urine in the sewage is high, the nitrogen content becomes excessive compared to the organic matter, and the nitrogen removal tends to be insufficient. In such a case, nitrous acid generated in the nitrification process or the denitrification process is accumulated. When the filtered water enters the decolorizing tank 140 while nitrous acid is accumulated, the nitrous acid is oxidized to nitric acid by consuming ozone. For this reason, there has been a problem that the amount of ozone to be used for decolorization decreases, the decolorization effect decreases, the chromaticity of the treated water increases, and the user feels uncomfortable.
[0004]
The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a circulating flush toilet and a method of purifying sewage of a circulating flush toilet capable of obtaining treated water having stable chromaticity. .
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the circulation flush toilet according to claim 1 is a flush toilet and a biological treatment tank that receives sewage from the flush toilet, decomposes organic matter in the sewage, and performs nitrification and denitrification. A filtration tank for solid-liquid separation of biologically treated water biologically treated in the biological treatment tank, and a decolorization tank for decolorizing the filtered water by blowing ozone gas into the filtered water solid-liquid separated in the filtration tank. In a circulating flush toilet configured to circulate the treated water decolorized in the decolorization tank as the wash water to the flush toilet, the chromaticity of the treated water decolorized in the decolorization tank is continuously or intermittently. Chromaticity measuring means for measuring, organic matter supply means for supplying easily decomposable organic matter to the biological treatment tank, when the chromaticity of the treated water exceeds a predetermined set value, the biological treatment tank A certain amount of said ease Characterized in that a control means for controlling the organic substance supply means to supply a solution of organic material.
[0006]
In the circulating flush toilet having this configuration, the biological treatment tank decomposes organic matter in the sewage received from the flush toilet, and performs nitrification and denitrification treatment to send the treated water to the filter tank as biological treatment water. Next, the filtration tank performs solid-liquid separation of the biological treatment water. The filtered water that has been subjected to solid-liquid separation is sent to a decolorization tank, where ozone gas is blown in the decolorization tank to be decolorized. Further, the chromaticity measuring means measures the chromaticity of the decolorized treated water, and when the chromaticity exceeds a predetermined set value, the control means controls the organic matter supply means to supply a predetermined amount to the biological treatment tank. Supplies easily decomposable organic substances. Further, the decolorized treated water is circulated to the flush toilet as washing water. The cause of the increase in the chromaticity of the treated water measured in this way is that the nitrogen content in the sewage is excessive (the C / N ratio is small) compared to the organic matter. It is conceivable that nitrous acid is not accumulated and accumulates. As a result, since nitrous acid obtains oxygen from ozone and turns into nitric acid in the decolorizing tank, ozone cannot be sufficiently used for the decolorizing treatment. In such a case, if the easily decomposable organic matter is supplied to the biological treatment tank, the denitrification treatment is promoted, the accumulation of nitrous acid is suppressed, and the decolorization treatment is sufficiently performed in the decolorization tank without increasing the supply amount of ozone. Thus, treated water having a stable chromaticity can be obtained.
[0007]
The method for purifying sewage of a circulating flush toilet according to claim 2 is a biological treatment step of receiving sewage from a flush toilet, decomposing organic matter in the sewage, and nitrifying and denitrifying the biological waste. A filtration step of solid-liquid separation of the treated biological treated water, a decolorization step of decolorizing the filtered water by blowing ozone gas into the filtered water subjected to solid-liquid separation in the filtration step, and a decolorization treatment in the decolorization step A chromaticity measuring step of continuously or intermittently measuring the chromaticity of water, and when the chromaticity of the treated water measured in the chromaticity measuring step exceeds a predetermined set value, the biological treatment An organic substance supply step of supplying a fixed amount of easily decomposable organic substance to the step.
[0008]
In the sewage purification method of the circulating flush toilet of this configuration, the organic matter in the sewage received from the flush toilet is decomposed, nitrified and denitrified, the treated biologically treated water is separated into solid and liquid, filtered, and filtered water. The filtered water is decolorized by blowing ozone gas into the filter. Then, the chromaticity of the decolorized treated water is measured continuously or intermittently, and when the measured chromaticity of the treated water exceeds a predetermined set value, a certain amount of easily decomposable organic matter is removed. Supply. The cause of the increase in the chromaticity of the treated water measured in this way is that the nitrogen content in the wastewater is excessive (the C / N ratio is small) compared to the organic matter. It is conceivable that the nitrite is accumulated as it is without changing to the above, and the nitrogen removal is not sufficiently performed. As a result, since nitrous acid obtains oxygen from ozone to become nitric acid, ozone cannot be sufficiently used for the decolorizing treatment. In such a case, if the easily decomposable organic substance is supplied, the denitrification treatment is promoted, the accumulation of nitrous acid is suppressed, and the decolorization treatment can be sufficiently performed without increasing the supply amount of ozone, and the stable color is obtained. The degree of treated water can be obtained.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a sewage purification apparatus embodying the present invention will be described with reference to the drawings. First, the configuration of the circulating flush toilet 1 will be described with reference to FIGS. FIG. 1 is a conceptual diagram of the circulating flush toilet 1 of the present embodiment, and FIG. 2 is a configuration diagram of the circulating flush toilet 1 of the present embodiment. As shown in FIG. 1, the circulation flush toilet 1 includes a flush toilet 5, a biological treatment tank 6 that receives sewage from the flush toilet 5, decomposes organic matter contained in the sewage, and performs nitrification and denitrification processing. A filtration tank 7 for solid-liquid separation of biologically treated water biologically treated in the treatment tank 6, a decolorization tank 8 for oxidizing and decolorizing the filtered water with ozone, and a treated water oxidized and decolorized in the decolorization tank 8 once. A treated water tank 10 for storing, a chromaticity meter 9 for measuring the chromaticity of the treated water oxidized and decolorized in the decolorizing tank 8, and a pump 12 based on the chromaticity measured by the chromaticity meter 9. The control device 11 includes a pump 12 for supplying a predetermined amount of easily decomposable organic matter stored in the easily decomposable organic matter tank 13 to the biological treatment tank 6 based on a signal from the control device 11.
[0010]
As shown in FIG. 2, the biological treatment tank 6 comprises an aeration tank 6b for nitrifying ammonia in sewage and converting it into nitric acid, and a denitrification treatment for nitric acid which has been nitrified in the aeration tank 6b to convert it into nitrogen gas. The denitrification tanks 6a are configured to be separated from each other. The sewage from the flush toilet 5 passes through the denitrification tank 6a, and the ammonia in the sewage is nitrified in the aeration tank 6b to be converted to nitric acid. The biologically treated water decomposed by the organic substance in the biological treatment tank 6 is then subjected to solid-liquid separation in the filtration tank 7 by the filtration membrane 7a. The filtered water solid-liquid separated in the filtration tank 7 is oxidized and decolorized in the decolorization tank 8 by the ozone generated by the ozone generator 18. The aeration tank 6b and the filtration tank 7 are connected to an air blower 17a, and high-pressure air generated by the air blower 17a is sent to each tank through the diffuser pipes 17b and 17c. Further, in the denitrification tank 6a, as shown in FIG. 2, the activated sludge and the sewage are stirred by the stirrer 15, so that the contact between the microorganisms in the activated sludge and the organic matter is promoted.
[0011]
Further, as shown in FIG. 2, the residual sludge by the solid-liquid separation in the filtration tank 7 is circulated by a circulation pump (not shown) and flows into the denitrification tank 6a of the biological treatment tank 6. In the denitrification tank 6a, nitric acid contained in the sludge that has flowed in is denitrified and released into the atmosphere as nitrogen gas. The filtered water that has been solid-liquid separated in the filtration tank 7 is oxidized by the ozone generated in the ozone generator 18 in the decolorization tank 8 and decolorized by decomposing the chromaticity components in the filtered water. At the same time, in the decolorizing tank 8, the hardly biodegradable organic matter in the filtered water is converted into easily decomposable organic matter. Here, in the nitrification treatment performed in the aeration tank 6b, only nitrous acid is changed to nitrite, and when nitrification is not performed, nitric acid is converted from ozone to oxygen in the decolorization tank 8 to be nitric acid. The treated water that has been oxidized (decolorized) in the decolorizing tank 8 is temporarily stored in a treated water tank 10. Then, the water is returned to the flush toilet 5 by a circulation pump (not shown), and is reused as washing water. The treated water does not necessarily have to be stored in the treated water tank 10 and may be returned to the flush toilet 5 directly from the decolorization tank 8 by a circulation pump.
[0012]
Here, a chromaticity meter 9 is installed in a pipe from the decolorization tank 8 to the treated water tank 10. The chromaticity meter 9 used in the present embodiment uses a transmitted light measurement method, which measures the degree of light yellow to yellowish brown of water to be measured by an absorbance method at an absorbance near a wavelength of 390 nm. Is what you do. If a continuous chromaticity meter is used, chromaticity can be measured continuously or intermittently. The chromaticity meter 9 measures the chromaticity of the treated water that has been oxidized in the decolorization tank 8, and sends the measurement result to the control device 11. The controller 11 compares the received chromaticity with a preset chromaticity (100 degrees in the present embodiment), and controls the pump 12 to operate when the chromaticity exceeds the set value.
[0013]
The pump 12, which is a component of the organic substance supply means, is a liquid feed pump such as a well-known tube pump, and operates according to an operation signal from the control device 11 to remove a certain amount of easily decomposable organic substances from the easily decomposable organic substance tank 13. It is sent to the denitrification tank 6a and stopped in accordance with a stop signal from the control device 11 to stop sending easily decomposable organic matter. The organic material supply means is not limited to a pump, and may be configured to open and close gravity drop with a solenoid. The easily decomposable organic matter to be supplied to the denitrification tank 6a is not particularly limited as long as it can exert a denitrification action by microorganisms, and examples thereof include sodium acetate, sodium citrate, glucose, and methanol. . In addition, here, the easily decomposable organic substance is supplied in a liquid form, but the liquid is not limited to a liquid as long as it can supply a constant amount. For example, a solid such as a tablet or powder is measured and dropped in a fixed amount. It may be configured as follows.
[0014]
Next, control of the pump 12 by the control device 11 will be described with reference to FIG. FIG. 3 is a flowchart of the pump control process of the control device 11. First, the chromaticity of the treated water measured by the chromaticity meter 9 is received (S1). Then, it is determined whether the chromaticity is 100 degrees or more (S3). When the temperature exceeds 100 degrees, it is determined that the decolorizing effect of ozone is reduced. When the angle is 100 degrees or more, the yellow color is strongly felt, and the user is more likely to feel uncomfortable. If the chromaticity is 100 degrees or more (S3: YES), an operation signal is transmitted to the pump 12 (S5). Upon receiving the operation signal, the pump 12 causes a fixed amount of easily decomposable organic matter to be sent from the easily decomposable organic matter tank 13 to the denitrification tank 6a. When the easily decomposable organic substance is supplied, the denitrification treatment is promoted in the denitrification tank 6a, and the accumulation of nitrous acid decreases. Therefore, the chromaticity gradually decreases.
[0015]
If the chromaticity is not 100 degrees or more (S3: NO), it is determined that the chromaticity of the treated water is normal, and a stop signal is transmitted to the pump 12 (S7). Upon receiving the stop signal, the pump 12 stops sending the easily decomposable organic matter when it is operating. If it has already stopped, nothing is done while it is stopped. The control device 11 repeats the above processing.
[0016]
As described above, the pump 12 operates based on the chromaticity measured by the chromaticity meter 9 and sends the easily decomposable organic matter from the easily decomposable organic matter tank 13 to the denitrification tank 6a. The pump 12 is operated intermittently at a preset time interval. Even if the operation signal is continuously received, the pump 12 is not operated unless the set time has elapsed. Further, the pump 12 may be operated in a concentrated manner during a time period such as nighttime when the number of users is small.
[0017]
As described above, according to the circulating flush toilet of the present embodiment, the chromaticity of the treated water decolorized in the decolorization tank 8 is continuously or intermittently monitored, and the chromaticity becomes 100 degrees or more. In such a case, the easily decomposable organic matter is supplied to the denitrification tank 6a by controlling the pump 12, thereby promoting the denitrification treatment in the denitrification tank 6a. As a result, the accumulation of nitrous acid in the filtered water is reduced, and ozone can be sufficiently used in the decolorization tank 8 for the decolorization treatment, and the chromaticity is restored. Therefore, treated water having stable chromaticity can be obtained without adding ozone. In particular, there is an effect capable of coping with a case where the ratio of the organic matter and the nitrogen content in the sewage varies greatly.
[0018]
Note that the present invention is not limited to the above embodiment, and various modifications are possible. For example, FIG. 4 is a flowchart of another form of pump control processing. In this embodiment, the pump 12 is operated when the chromaticity becomes 100 degrees or more, the easily decomposable organic matter is supplied to the denitrification tank 6a, and the operation is stopped when the chromaticity falls below 40 degrees as a result of continuing the operation. Is controlled as follows. Specifically, first, the chromaticity of the treated water measured by the chromaticity meter 9 is received (S11). Then, it is determined whether the chromaticity is 100 degrees or more (S13). If the chromaticity is 100 degrees or more (S13: YES), an operation signal is transmitted to the pump 12 (S15). Upon receiving the operation signal, the pump 12 causes a fixed amount of easily decomposable organic matter to be sent from the easily decomposable organic matter tank 13 to the denitrification tank 6a. When the easily decomposable organic substance is supplied, the denitrification treatment is promoted in the denitrification tank 6a, and the accumulation of nitrous acid decreases. Therefore, the chromaticity gradually decreases. Then, the chromaticity is received again from the chromaticity meter 9 (S17). If the chromaticity is 40 degrees or more (S19: YES), the operation signal is continuously transmitted to the pump 12 (S15). In response to this, the pump 12 continuously sends a fixed amount of easily decomposable organic matter from the easily decomposable organic substance tank 13 to the denitrification tank 6a. Then, S15 to S19 are repeated until the chromaticity falls below 40 degrees. The pump 12 is operated intermittently as in the above embodiment. If the chromaticity is not 40 degrees or more (S19: NO), it is determined that the chromaticity of the treated water has returned to normal, and a stop signal is transmitted to the pump 12 (S21). If the chromaticity received in S11 is not 100 degrees or more (S13: NO), it is determined that the chromaticity of the treated water is normal, and a stop signal is transmitted to the pump 12 (S21). Upon receiving the stop signal, the pump 12 stops sending the easily decomposable organic matter when it is operating. If it has already stopped, nothing is done while it is stopped. In this embodiment, the chromaticity is continuously monitored, and the supply of the easily decomposable organic substance is stopped when the chromaticity reaches 40 degrees, which is usually referred to as the upper limit of the water content. The chromaticity at which the supply is stopped is not limited to 40 degrees, and can be appropriately set according to the installation environment.
[0019]
【The invention's effect】
As is clear from the above description, according to the circulating flush toilet according to claim 1, the chromaticity of the treated water is measured continuously or intermittently. The denitrification treatment can be promoted by supplying easily decomposable organic substances to the solution, and the accumulation of nitrous acid, which is one of the causes of high chromaticity, can be eliminated. Therefore, the state in which the ozone decolorization process cannot keep up with the excess nitrous acid is also eliminated, so that the decolorization process can be sufficiently performed in the decolorization tank without increasing the supply amount of ozone, and the treated water having a stable chromaticity can be obtained. Can be obtained.
[0020]
According to the method for purifying circulated flush toilets according to claim 2, since the chromaticity of the treated water is measured continuously or intermittently, when the chromaticity increases, easily decomposable organic substances are supplied. To promote the denitrification treatment, and eliminate the accumulation of nitrous acid, which is one of the causes of the increase in chromaticity. Therefore, the state in which the ozone decolorization process cannot keep up with the excess nitrous acid is also resolved, so that the decolorization process can be performed sufficiently without increasing the supply amount of ozone, and the treated water having a stable chromaticity can be obtained. Can be.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a circulating flush toilet 1 of the present embodiment.
FIG. 2 is a configuration diagram of a circulation type flush toilet 1 of the present embodiment.
FIG. 3 is a flowchart of a pump control process of the control device 11;
FIG. 4 is a flowchart of another embodiment of a pump control process.
FIG. 5 is a conceptual diagram of a conventional circulating flush toilet 1.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Circulating flush toilet 5 Washing toilet 6 Biological treatment tank 7 Filtration tank 8 Decolorization tank 9 Chromaticity meter 11 Controller 12 Pump 13 Easy-to-decompose organic matter tank

Claims (2)

A flush toilet, a biological treatment tank that receives sewage from the flush toilet, decomposes organic matter in the sewage, and performs nitrification and denitrification treatment; and filtration for solid-liquid separation of biologically treated water biologically treated in the biological treatment tank. A tank, and a decolorization tank for decolorizing the filtered water by blowing ozone gas into the filtered water that has been solid-liquid separated in the filtration tank, wherein the treated water that has been decolorized in the decolorization tank is used as washing water for the flush toilet. In a circulating flush toilet that is circulated,
Chromaticity measuring means for continuously or intermittently measuring the chromaticity of the treated water decolorized in the decolorizing tank,
Organic substance supply means for supplying the easily decomposable organic substance to the biological treatment tank,
Control means for controlling the organic substance supply means so as to supply a constant amount of the easily decomposable organic substance to the biological treatment tank when the chromaticity of the treated water exceeds a predetermined set value. A flush flush toilet characterized by the following. A biological treatment step of receiving sewage from the flush toilet, decomposing organic matter in the sewage, and nitrifying and denitrifying;
A filtration step of solid-liquid separation of biologically treated water biologically treated in the biological treatment step,
A decolorizing step of decolorizing the filtered water by blowing ozone gas into the filtered water subjected to solid-liquid separation in the filtration step,
A chromaticity measurement step of continuously or intermittently measuring the chromaticity of the treated water that has been decolorized in the decolorization step,
When the chromaticity of the treated water measured in the chromaticity measurement step exceeds a predetermined set value, a circulation comprising an organic substance supply step of supplying a fixed amount of easily decomposable organic substances to the biological treatment step How to purify sewage from flush toilets.

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